Synopsis:
In a time when there were infinite Earths, the greatest heroes of two worlds would regularly cross the dimensional barrier to vanquish the threats that faced them both. Earth-One's Justice League of America, composed of powerful young adventurers at the beginning of their careers and Earth-Two's Justice Society of America, an organization of legendary champions of truth returning from retirement, team up to face the threats of a new generation.

In these eight Silver Age classics, the wondrous Wildcat is back in action to aid his former JSA teammates, as their old enemies hunt down Starman and Black Canary, and he also assists the supernatural sleuth, the Spectre. Plus, Flash, Green Lantern, and the Atom meet their counterparts to ward off powerful enemies who seek to destroy the heroes, their loved ones and the multiverse itself! (from the back cover)